1. Field of Invention
The present invention pertains to the field of automated reasoning. More particularly, this invention relates to Bayesian networks in automated reasoning.
2. Art Background
Bayesian networks are commonly used for automated reasoning in a wide variety of applications. Typically, Bayesian networks are used to model an underlying system or environment of interest. For example, Bayesian networks may be used to model biological systems including humans and animals, electrical systems, mechanical systems, software systems, business transaction systems, etc. Bayesian networks may be useful in a variety of automated reasoning tasks including diagnosing problems with an underlying system, determining the health of an underlying system, and predicting future events in an underlying system to name a few examples.
A typical Bayesian network is a graph structure having a set of nodes and interconnecting arcs that define parent-child relationships among the nodes. A Bayesian network also includes a set of Bayesian network parameters which are associated with the nodes of the graph structure. Typically, the nodes of a Bayesian network are associated with events or characteristics of the underlying modeled environment and the Bayesian network parameters usually indicate partial causalities among the events or characteristics associated with the nodes. The Bayesian network parameters are commonly contained in conditional probability tables associated with the nodes. Typically, a Bayesian network describes the joint probability of random variables each of which is represented by a node in the graph.
The Bayesian network parameters are commonly obtained from experts who possess knowledge of the behaviors or characteristics of the underlying modeled environment. Alternatively, the Bayesian network parameters may be obtained using observations of the underlying modeled environment. Unfortunately, environments may exist for which experts are unavailable or prohibitively expensive. In addition, environments may exist for which observation data is scarce or in which the underlying environment changes and renders past experience or observations obsolete.